1. Field of the Invention
This invention relates, in general, to hydraulic couplings, and specifically to hydraulic couplings used in undersea drilling and production applications. More particularly, the invention involves undersea hydraulic couplings having seal retainers that hold and retain seals between the coupling members.
2. Description of Related Art
Subsea hydraulic couplings are old in the art. The couplings generally consist of a male member and a female member with seals to seal the junction between the male and female members. The female member generally has a cylindrical body with a relatively large diameter bore at one end and a relatively small diameter bore at the other. The small bore facilitates connections to hydraulic lines, while the large bore contains the seals and receives the male portion of the coupling. The male member includes a probe section insertable into the large bore of the female member. According to various embodiments of the device, the seals either abut the end, or face, of the male member or engage the male member about its outer circumference. Hydraulic fluid is then free to flow through the female and male portions of the coupling and seals prevent that flow from escaping about the joints of the coupling.
Optionally, a check valve may be installed in the female member and also in the male member. Each check valve is open when the coupling is made up; however, each check valve closes when the coupling is broken so as to prevent fluid from leaking out of the system of which the coupling is part.
In U.S. Pat. Nos. 4,694,859 and 5,762,106 to Robert E. Smith III, an undersea hydraulic coupling and metal seal is disclosed. A reusable metal seal engages the circumference of the probe when it is positioned within the female member body. The seal is held in place by a cylindrical seal retainer. When the male and female portions of the coupling are parted under pressure, the seal retainer prevents the metal seal from blowing out through the bore of the female member.
U.S. Pat. Nos. 4,900,071 and 5,052,439 to Robert E. Smith III disclose an undersea hydraulic coupling with an elastomeric seal that is restrained from radial movement into the central bore of the female member by a circumferential shoulder on one or both surfaces adjacent the seal. Preferably, the seal has a dovetail interfit with one or both surfaces. U.S. Pat. Nos. 5,099,882, 5,203,374, 5,232,021 to Robert E. Smith III also show undersea hydraulic couplings with these seals. An inner cylindrical surface of the annular seal engages the circumference of the male member or probe as the probe is inserted into the female member. As the male member or probe is pulled out of the female member bore, the leading face of the male member reaches the soft annular seal intermediate that bore. When the face reaches the midpoint of the soft annular seal, the dovetail interfit prevents the seal being imploded into the bore, as the seawater and/or hydraulic fluid enter the bore at high pressure.
To retain one or more seals in the female member of an undersea hydraulic coupling, a seal retainer may be connected to the female member. The seal retainer may be a generally sleeve-shaped cylindrical body that is inserted into the bore of the female member until the seal retainer abuts a shoulder in the bore of the female member. To secure the seal retainer against the shoulder, a retainer locking member may also be attached to the female member using threads or snap rings, for example. A radial seal may be retained by the seal retainer. For example, the seal retainer may hold a pressure energized radial metal seal on a shoulder in the female member bore.
Although seals that are retained in the female coupling members of subsea hydraulic couplings may be reusable, the seals periodically may be removed and/or replaced. To remove the seals, the male coupling member must be disconnected from the female coupling member, and the seal retainer must be disconnected and disengaged from the female coupling member.
Seals that are retained in the bore of the female coupling member may be difficult to reach because of the length and narrow diameter of the female bore. In some cases, seals may become stuck in the female member bore because of wear or deformation of the seals, or because the outer diameter of the seals become compressed against the wall of the female member bore adjacent the shoulder on which the seals are positioned.
Removing and replacing seals in undersea hydraulic couplings may be difficult without a tool to reach into the female member bore and pry or pull the seal out. However, the tool may scratch the female member bore and damage the sealing surfaces. For these reasons, removing and replacing the seals in undersea hydraulic couplings is a problem.
Thus, undersea hydraulic couplings are needed having retained seals that may be easily removed and replaced. Undersea hydraulic couplings also are needed that have retained seals that may be removed and replaced without damage to the coupling, and especially without damage to the sealing surfaces. Undersea hydraulic couplings are needed with seal retainers that reduce or eliminate the need for a tool to remove and replace seals from the bore of the female coupling member.